27th December 2008

This one is very old and standard.. but good for those who dont know....

Prove that a function can be written as a sum of an even and odd function.

(Also: What is the condition for this to be written as above!)

14 Answers

9
Celestine preetham ·

its domain must be symmetrical abt o

sry jus typed as soon as i saw

62
Lokesh Verma ·

good one Celestine :)

62
Lokesh Verma ·

can someone else give the reason etc?

33
Abhishek Priyam ·

range or domain [7]

62
Lokesh Verma ·

yes priyam it is the domain... my wrong...

I just din read properly.. all i read was symmetic :D :P

11
Anirudh Narayanan ·

Explanation anyone? I'm completely lost [2]

62
Lokesh Verma ·

what is said about

f(x) + f(-x)

and

f(x) - f(-x)

11
Anirudh Narayanan ·

[7][7][7][7][7]

I don't know [2]

1
Philip Calvert ·

f(x) + f(-x) =0 for odd functions

and

f(x) - f(-x) =0 for even functions

62
Lokesh Verma ·

so does that give us something about the solution?

62
Lokesh Verma ·

I mean the final answer to the main question?

62
Lokesh Verma ·

A very very old one that no one has replied to yet!

1
rickde ·

assume domain symmetrical about origin

let f(x) be the function
f(x)=f(x)
or 2f(x)=2f(x)
=>2f(x)=f(x)+f(x)+f(-x)-f(-x)
=>2f(x)=(f(x)+f(-x))+(f(x)-f(-x))

=> f(x)= (f(x)+f(-x))/2 + (f(x)-f(-x))/2

for the first function replacing x→ -x does not change the function
hence it is even

for the second one x→ -x gives f(-x)=-f(x) hence it is even

thus we can show f(x) as a sum two functions one even and one odd

62
Lokesh Verma ·

Good work :)

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